Re: RFC: Hashing by VIF addr for rx of data packets.

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2013-04-03 at 06:37 -0700, Ben Greear wrote:
> > Hmmm. I'm not really convinced this will make sense upstream. I'm kinda
> > fine with the single-station cache, but maintaining a whole other hash
> > table seems too much overhead for every use case but yours.
> 
> Yeah, aside from multiple stations, I'm not sure it helps anything.  It would
> require a different scheme to help with multiple VAP I think, and I'm not
> sure there are any other multi-vif use cases out there...

Yes, likely.

> >> +		if (!is_multicast_ether_addr(hdr->addr1)) {
> >> +			sta = sta_info_get_by_vif(local, hdr->addr1);
> >
> > AFAICT, this is also wrong for TDLS and other cases where we might
> > receive a frame that's not from the AP, even if it's only by accident or
> > from an attacker.
> 
> I think patch is probably wrong for any VIF that can be associated with more than
> one station (such as APs).  I'm going to re-work the vhash to only include
> Station VIFS and see how that works for my test case.

Well it's wrong even as is, even with just a single station on that VIF,
because as far as I can tell it assumes that *any* frame, no matter who
it came from, was from that station.

johannes